Distribution transformers are used in AC power systems in order to convert high-voltage electricity carried by power lines to lower-voltage electricity that may be used by consumers. Several varieties of distribution transformer exist: pole-mounted transformers (mounted on a utility pole), ground-level pad-mounted transformers (generally mounted on a surface-level concrete pad), and underground transformers. These transformers may include, among other components, a core clamping structure that keeps the coils of the transformer in place.
These distribution transformers are legally required to meet efficiency standards set forth by the Department of Energy (DOE). Because of these requirements, and because of the demands of a competitive marketplace, it may generally be necessary to maintain stray losses in a given distribution transformer at as low a level as possible. Stray losses in a distribution transformer design can be caused by metallic structural components such as the transformer core clamps (typically made from mild steel), the tie plates, the transformer tank, and other similar metallic structural components.
Some of these components, such as the mild steel core clamps, may also add significant weight to the overall transformer. This may also be undesirable, especially in those cases where the distribution transformer is intended to be mounted on a utility pole; increased transformer weight may mean increased material and installation costs or increased risk of failure. As such, it is competitively very important to reduce both the sources of stray losses in a distribution transformer and the weight of the distribution transformer, so long as each can be done cost-effectively.